1. Field of the Invention
The present invention relates to a musical tone signal generating technology, and more particularly to a musical tone signal generating technology capable of controlling the qualities of a tone signal in accordance with human auditory senses.
2. Description of the Related Art
Natural musical instruments generate a variety of musical sounds depending on their kinds, performance techniques, and differences between instruments.
Electronic musical instruments can also generate a variety of musical sounds by changing input signals, electrical parameters, and circuit parameters, although generated musical sounds depend more or less on the type of a musical tone signal synthesizer. By editing electrical parameters and circuit parameters, it is possible to generate not only musical sounds of natural musical instruments but also musical sounds having a diversity of tone colors.
An envelope of an attenuating type musical tone signal such as a tone signal of a piano is generally decomposed into an attack (A), a decay (D), a sustain (S), and a release (R). The waveform of such a tone signal can be analyzed and synthesized by changing the level and rate of these parameters.
In a synthesizer or the like, A, D, S, and R envelope shapes and sinal waveforms themselves are directly controlled. A player of a synthesizer has been required to control electrical parameters and circuit parameters of a sound source circuit in order to produce desired musical sounds.
It is therefore necessary for a player to have knowledge of which parts of a synthesizer are operated in what manner in order to make musical sounds slightly "sharp" or "soft". In addition, such an operation by a player is very cumbersome.
An electronic musical instrument ("ELECTONE" available from Yamaha, Japan) having a slider unit called a "brilliance" unit is known. The brilliance slider unit can change only the peak level of an FM sound source.
The qualities of musical sounds can be defined easily by using sensory expressions such as "warmness", "sharpness", and "brightness".
The qualities of tone signals generated by a sound source circuit can be defined easily by electrical parameters and circuit parameters such as envelope, frequency characteristics, vibrato, and localization (orientation).
It is not easy to have a definite correspondence between sensory expressions of tone colors, and electrical parameters and circuit parameters. It is difficult for a beginner to produce desired musical tones.
Recently, fuzzy logics have been used in various technical fields. Also in the field of electronic musical instruments, a technique has been proposed as disclosed, for example, in JP-A-2-146094. According to this technique, an envelope of a musical tone signal is controlled through fuzzy calculations using an initial touch representing the key depression speed and a key-on time representing a time while the key is maintained depressed.